Magnetron having wave-guide output



April 12, 1960 J. A. VAN DE GOOR ETAL 2,932,767

MAGNETRON HAVING WAVE-GUIDE OUTPUT Filed March 18, 1958 5 4 a s FIGQ IN NT'OR JOHANNES AN IUS VAN DE R KARL WALTER HINKEL BY M &

AGENT i atented Apr. 12, 1960 had 2,932,767 MAGNETRON HAVING WAVE-GUIDE oUTPU'r Johannes Antonius Van tle Gear and Karl Walter Hinkel, Eindhoven, Netherlands, assignors to North American Philips Company, inc, New York, N.Y., a corporation of Delaware Application March 18, 1958, Serial No. 722,237 Claims priority, application Netherlands March 30, 1957 2 Claims. (Cl. 315-39) This invention relates to a magnetron having a waveguide output for connection to a wave-guide of rectangular cross-section, in which, starting from a split-shaped aperture in one of the resonant cavities within a waveguide of circular cross-section, two opposed wall portions diverge in the direction of the glass window at the end of the wave-guide.

In the known magnetrons of the abovementioned kind, the window is mounted in a dished cover which together with a rim soldered to the end of the Wave-guide produces a filter slit which extends at right-angles to the wave-guide axis. The connecting flange having a rectangular aperture is soldered to the magnetron by means of a conductive cylinder the diameter of which is larger than the dished closing member of the wave-guide. This construction is comparatively bulky and its manufacture is relatively expensive.

Magnetrons are also known in which two diverging wall parts in a wave-guide are used and in which both the wave-guide output and the wave-guide to be connected thereto have either circular or rectangular cross-sections. The circular cross-section has a limitation in that a transition to the rectangular cross-section is still required, while the rectangular shape suliers from the disadvantage that it requires a comparatively expensive construction in view of the connection to the anode block of the magnetron.

Magnetrons are also known in which the diverging wall parts extend in a wave-guide having two parallel walls to which two semi-circular walls of gradually increasing size are joined. However, such a construction is very expensive.

It is an object of the present invention to provide a construction of the kind described in the opening part which can be cheaply manufactured and has a very small size.

According to the invention, in a magnetron having a wave-guide output suited for connection to a wave-guide having rectangular cross-section in which, starting from a slit-shaped aperture in one of the resonant cavities in a wave-guide of circular cross-section, two opposed wall parts diverge from the aperture in the direction of the glass window at the end of the wave-guide, the glass window is mounted in a flat connecting flange which with the aid of a conducting cylinder is secured to the magnetron casing so that between this conducting cylinder and the outer surface of the wave-guide, which extends closely up to the flange, a narrow filter slit is left the bottom of which is spaced away from the flange by a distance of from one quarter to one half of the operating wave-length.

In order that the invention may readily be carried out, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which- Fig. 1 is a sectional view taken in the plane passing through the axes of the wave-guide and the magnetron, and

Fig. 2 is a sectional view taken in a plane passing through the axis of the waveguide at right angles to the axis of magnetron.

The magnetron parts which are not essential to the invention are shown diagrammatically only.

In the figures, reference numeral 1 designates the anode block of the magnetron having fin-shaped anode segments 2. A laterally extending conical wave-guide 3 is bored in the magnetron, two segments 4, which start from a narrow aperture 5 in one of the resonant cavities of the magnetron, extending in the direction of the glass Window 6 which is sealed in a flat flange 7. The flange 7 is soldered to the anode block by means of a conducting cylinder 8 so that a slit 9 is left between the cylinder 8 and the wave-guide. To the flange 7 there is directly connected at flange 1th of a rectangular wave-guide 11 having a smaller transverse dimension 0: and a larger transverse dimension b. The flange 10 is provided with a continuous annular filter slit 12 the depth of which is about one quarter of the operating wave-length. The output coupling described has a small length and its main ufacture is comparatively cheap since the conical wave guide can be bored directly in the anode block.

What is claimed is:

1. A magnetron comprising a hollow anode block having a plurality of tin-shaped anode segments defining a plurality of resonant cavities in said block, said block having an outward flaring bore defining a conical waveguide connected to one of said resonant cavities by an aperture in said anode block, a hollow electrically conducting cylinder surrounding the conical bore and secured at one end to said anode block and defining with said anode block a slit between said cylinder and said waveguide, a flange having a window therein for the transmission of electromagnetic waves secured at the other end to said electrically conducting cylinder, and a rectangular wave-guide having a flange at one end connected to the first-named flange, said latter flange having an annular slit therein the depth of which is about onequarter of the wave-length of the electromagnetic waves transmitted through the window.

2. A magnetron comprising a hollow anode block having a plurality of fin-shaped anode segments defining an axis of the magnetron and a plurality of resonant cavities around said axis, said block having an outwardly flaring bore defining a conical wave-guide connected to one of said resonant cavities by an aperture in said anode block, a hollow electrically conducting cylinder closed at one end by a flange having a window therein for the transmission of electromagnetic waves and secured at the other end to a shoulder on said anode block, said electrically conducting cylinder surrounding said conical wave-guide and defining with said anode block a slit between the wall of said wave-guide and the electrically conducting cylinder, a pair of segments lying in a plane normal to said axis extending in said wave-guide from said aperture toward said window and a rectangular wave-guide having a flange at one end secured to the flange at the end of the electrically conducting cylinder, said flange at the end of said rectangular wave-guide having an annular slit the depth of which is one-quarter of a wave-length of the electromagnetic waves transmitted through said window.

References Cited in the file of this patent UNITED STATES PATENTS 2,749,477 VerWeel June 5, 1956 2,768,327 Millman Oct. 23, 1956 2,820,924 Litton Ian. 21, 1958 

